1. Field of Invention:
This invention relates generally to the secondary containment of hazardous materials and residual wastes, and more particularly to a secondary containment structure which, depending on its size, is adapted to serve as a pallet, the floor of a building or other enclosure for storing primary containers, or as a shelf for primary containers.
2. Status of Prior Art:
Modern industrial and commercial activity often result in the generation of residual materials and wastes that may be hazardous. Hazardous waste is any byproduct generated by this activity that is potentially dangerous to the environment or injurious to humans. The wastes, whether in solid, liquid or gaseous form, are considered to be hazardous if they possess any one of the following characteristics:
Characteristic A. The waste is toxic and if improperly handled may cause illness and other health problems.
Characteristic B. The waste is ignitable and may catch fire.
Characteristic C. The waste is corrosive and, on contact, is capable of corroding materials as well as human tissue.
Characteristic D. The waste is violently reactive with water and may cause an explosion.
The National Fire Protection Association defines hazardous materials as "any substance that by reason of being explosive, flammable, poisonous, corrosive, oxidizing, irritating or otherwise harmful, is likely to cause injury or death."
It is of the utmost importance that hazardous materials be handled and stored in a manner complying with prevailing regulatory agency requirements, environmental regulations and local ordinances covering such materials. The consequences of non-compliance with federal, state or municipal codes may be very serious to those companies which generate hazardous materials, for not only will they be subjected to heavy fines, but the officers of these companies may be held criminally liable for any accident resulting in death or injury.
Under existing environmental protection agency regulations, one must make use of primary containers such as drums, cans and bottles that are fabricated or lined with materials that will not react with and are otherwise compatible with the hazardous waste to be stored. Primary containers must always be closed during storage, except when it becomes necessary to add or remove waste. And primary containers holding hazardous wastes must not be opened, handled or stored in a manner that may rupture the container or cause it to leak.
Yet not all primary containers live up to these requirements, and their integrity may be impaired by severe rusting or other structural defects, as a result of which leakage is experienced.
In order to prevent the release of hazardous wastes from primary containers into the environment, the regulations calls for secondary containment systems so designed and operated as to prevent any migration of wastes or accumulated liquid out of the system to the soil, ground water or surface water. These regulations require that the capacity of the containment system must be sufficient to contain 10% of the volume of the container or the volume of the largest container, whichever is largest.
Various types of secondary containment structures are now commercially available. An elementary form of such structure is the spill containment tray sold under the trademark SAFE-T-TRAY by Safety Storage, Inc., of Campbell, Calif. This tray is formed of polypropylene and is provided with a spill grate of the same material. Thus if a bottle containing a hazardous liquid is to be stored on a shelf, the spill containment tray is placed on the shelf and the bottle is then rested on the spill grate, so that any leakage from the bottle is collected in the tray.
The Safety Storage Company also markets a portable hazardous liquid spill containment sump constructed of steel and provided with a fiberglass grating. This sump can accommodate as many as forty 55-gallon drums of hazardous liquid. The sump is provided with fork lift pockets for easy relocation inside or outside a plant. The sump is also provided with a drain to remove hazardous liquid collected therein.
The Utensco P&D Company of Port Washington, New York, makes metal pallets which can support two or four drums and which can be transported by fork lift trucks. The pallets include an internal catch basin to hold hazardous spills or leaks.
And the Precision Quincy Corporation of Woodstock, Ill., makes portable buildings of welded steel construction for storing hazardous waste drums, the building having a fiberglass flow grating and an under floor sump to collect and retain spillage or leakage.
Inasmuch as a secondary containment structure in accordance with the invention makes use of structural sandwich laminates in which an end grain balsa wood core is laminated to fiberglass-reinforced plastic facing skins, the patents to Lippay, 3,298,892, to Shook et al., 3,376,185, and to Kohn, 4,536,427 are of prior art interest.